Apparatus relating to molding units



J. D. SMITH July 9, 1929.

APPARATUS RELATING TO MOLDING UNITS Filed Sept. 20, 1923 3 Sheets-Sheet jfw e/vrar v (1 5507 /'/'/7 b APPARATUS RELATING TO MOLDING UNITS Filed Sept. 20, 1923 3 Sheets-Sheet 2 I E: L 6 7/ July 1929. J. D. S MITH 7 1,720,611

APPARATUS RELATING TO MOLDING UNITS Filed Sept. 20, 1925 3 Sheets-Sheet 3 Patented July 9, 1929.

UNITED STATES JOHN DENNISTON SMITH, OF DUNEDIN OTAGO, NEW ZEALAND.

APPARATUS RELATING TO MOLDING UNITS.

Application filed September 20, 1923. Serial No. 663,869.

This invention relates to the casting of lead heads on nails, and has for its principal object to provide a machine and process whereby lead-headed nails are produced entirely automatically and without the formation of blow-holes. Further objects are to feed the nails from bulk quantities in accordance with the consumption of the machine, to separate the bent, short, long, thick or clubpointed nails from the normal nails, and to automatically deliver the nails into holders by which they are carried to the mold into which molten metal is pumped so as thereby to cast the heads upon the nails. It will be appreciated that to ensure the automatic operation of the machine and the casting of the heads upon nails, it is necessary to provide means for automatically feeding them from bulk and for rejecting faulty nails which would otherwise cause a stoppage of the machine.

My invention consists in apparatus for the circulation of molten metal from the pot to the mold, filling the latter and directing the over-flow from the mold back into the pot; and in timing the actuations of mechanism employed to firstly advance a pot containing molten metal to engage with the mold plate, and simultaneously with the said engagement, to effect the descending movement of the pump plunger; secondly, to cause the return of a weight lever actuating member without operating upon the said plunger; thirdly to accomplish the disengagement of the pot and the mold plate and fourthly to return the plunger to its normal position.

The means employed to carry the above functions into effect includes a system of conduits and grooves; the said conduits aifording communication from the interior of the pot with grooves formed in the mouthpiece of the said pot, the said grooves in the mouthpiece having inter-communication with each other and with a runner leading to the mold; the intercomnmnication of the conduits being provided for the purpose of relieving the mouthpiece of surplus metal and for the expulsion of air. 7

The foregoing relates especially to molding units of the type having for its object the avoidance of interference by the presence of air in the mold more commonly referred to as blow holes; there are certain other novel features in combination with the said novel molding units to avoid blow holes which will be more fully explained below with reference to the accom anying drawings relatmg to apparatus for manufacturing lead headed nails.

Referring to the drawings,

Fig. 1 is a side elevation of the nail heading molding unit.

Fig. 2 is an enlarged view in section of the plunger casing and nail holder.

Fig. 3 is an enlarged sectional view of the pot and mold plate, a portion of the cylinder being shown.

Fig. 4 is a fragmentary view in elevation showing the face of the pot mold.

Fig. 5 is a front elevation showing the upper part of the molding unit.

Fig. 6 is a plan View of the spring shackle.

Fig. 7 is a side elevation of the upper part of the molding unit.

Fig. 8 is a perspective View showing a portion of the lower end casing at the bottom of the nail reservoir. 7

Fig. 9 is a plan view of the lower end casing at the bottom of the nail reservoir.

Fig. 10 is a plan view showing the lower end of the nail reservoir, the left hand View indicating'the nail in enlargement with the feed ready to be delivered to the leader aperture.

Fig. 11 is a cross section of the mold cylinder.

Fig. 12 is an elevation showing part of the mold cylinder.

Fig. 13 is a view showing the nail extractor grid mechanism.

Fig. 1a is a view of the mold pot showing plunger and weight levers, a portion of the pot being in section to more clearly indicate the pump plunger. I

Fig. 15 is a plan view showing the plunger and weight levers in top position.

Fig. 16 is the same view illustrating the parts in down position.

Fig. 17 is a detailed plan view of automatic stop molding mechanism.

Fig. 18 is an elevation of Fig. 17.

Referring now in detail to the several figures, the nails are deposited into a hopper 64 at the top of the molding machine, which turns upon a pivot 65 and oscillates through an angle approximately between twenty-five degrees above and twenty-five degrees below the horizontal, being actuated by the movement transmitted from a crank 66 mounted upon a. shaft 67. In the hopper 6 1 the nails 68 are arranged to hang downwardly sus pended by their heads through slots 64A in the bottom of the hopper 64, see Fig. 5. The nails are projected along the slots 64A into the slots 69, Fig. 10 of the reservoir 69A, and precipitated to the bottom 69B thereof, the foremost nail 68A lodging in the recess 68B of the feed bar 680; the recess 6813 being in line with the slots 69 for that purpose. There is a lateral motion transmitted to the feed bar 686, said lateral motion occurring when the plunger bar 70 reaches its top position, as indicated in Figure 5. There is a bell crank lever 68D, pivotally mounted on the frame of the unit at 68E, having its lower end engaging with the top surface of a wearing piece 68D and adapted to slide upon the plunger bar 70, while its upper end is coupled to a spring shackle 68F; the said wearing piece may be adjusted along the said bar 70 to miss the lower end of the bell crank lever 68D and thus stop lateral movement of the feed bar 68C; the said shackle is an elastic medium between the positive movement of the bell crank lever, and the feed bar 680, to take up a shock of resistance that may be caused through a nail, or nails becoming jammed during its or their delivery to the leader aperture 68G from which it is delivered to the upper part of the feeder 71. The feeder 71 receive the said nails one by one, and direct them through the lower tube 72 to the plunger casing 7 3, there to be retained in the nail holder 73A, with the points of the nails directly over the holes 74 in the nipple 7 5 of the molding cylinder? 6 the latter being mounted on a spindle 76A, see Fig. 11. The nails 68 are pressed into the nipples 7 5 by means of a series of plungers 77, Fig. 2, the said plungers being suitably mounted upon the bar 70, which is adapted to move vertically in guides A provided in the frame 78 of the imit. The said plungers 77 project downwardly, and the vertical motion is transmitted thereto through the bar 7 0 by a cam not shown mounted on the cam shaft 79 which actuates lever 79, link 79, lever 79 which is connected to a pitman 79 the upper andlower ends only of which are designated in Fig. 1, the intermediate part being broken away to show the parts beneath. On the downward stroke of the plunger the nail is forced through the nail holder 73A into the hole 7 1 of the nipple 75, see Figs. 1

and 11. The said nipple 7 5 is fashioned preferably in the manner indicated in Figures 11 and 12 respectively, the snap head A thereof forming the underside of the mold of the lead head; there is a threaded port-ion 75B formed to register with a threaded portion in the cylinder 76, and a tapered portion 7 5G projecting inwards from the said threaded part 7513, there being a spring 751) normally closing the tapered hole 74 at its inner end as shown on the right hand side of Fig. 11 when the plungers force the nail through the hole 74 of the nipple 75, it is against the influence of the spring 75D, and on the plunger 77 retiring, the nail is held in the nipple, with its head projecting the desired distance, due to the said influence of the spring 75]).

The point 82 of the nail 68 is adapted to engage with wiper plates 88 which are pivot ally mounted within thecylinder 76 at Set, and are actuated by a cam 85 to partially eject the nail to enable it to engage, inthe course of the revolution of the cylinder, with an extracting grid, 86, Figure 13 which has a downward movement transmitted thereto simultaneously with the downward motion of th plungers 77 when replenishing the top line of nails. The nails extracted are finished nails, and have lead heads cast thereon.

The molding cylinder 76 has an intermittent rotating motion transmitted thereto, by means of the ratchet movement 7 6B, the said cylinder coming to rest four times in a revolution, a fresh nail being introduced to the nipple 75 by the plungers 77 at each rest. Upon the first quarter of a revolution of the molding cylinder. the first said line of nails is brought opposite the mouth 87 of the molding pot 88. There is a crucible. not shown in the drawings, with a conduit providing a constant molten metal supply to the pot 88; the said pot, which is adapted to'contain the metal is provided with an open cylinder 89, and a plunger 90; the plunger movement is controlled by cams mounted upon the cam shaft 79 and the pot oscillates to and from contact, through the medium of the mold plate 91 with the molding cylinder 76, the oscillations synchronizing with the movement of the plunger 90 to feed the molten lead to the mold plate 91; that is to say, on the downward stroke of the plunger, the molten metal is forced through the channel 92 to the runner 93 and into the mold 94:, while the said mouth is in contact with the mold plate, which said mold plate forms contact with the mold cylinder 76, containing the nail upon which the head is to be cast. Before, however, the plunger 90 commences its upward stroke, the pot 88 recedes from contact with the mold plate 91; this precaution is neces sary so that there will be no suction on the newly molded nail head which is still to a degree, in a molten state. The mechanism, for carrying this movement into effect comprises two cams, each operating a separate lever 95 and 96 mounted on the same shaft 97, one of the said levers being keyed and one pivotally mounted on the said shaft 97.

The boss part 95A. and 96A of the levers 95 and 96 are provided with clutch faces, 95B and 9613, there being sufficient play between the faces for the cams to operate the levers independently of each other. hen the levers 95 and 96 are in normal position, that is, when the pump plunger is in its top position, the clutch faces are in engagement. On the cams performing a partial revolution, the weight lever 96 and the lever actuating the plunger 90 drop simultaneously under the influence of a weight 96C held normally in suspension due to the engagement of the cam with the said weight lever, and the said cam is so fashioned that on a continuation of its revolution, the weight lever 96 is lifted before the cam actuating the disengagement of the pot S8 with the mold plate 91 comes into operation to relieve the pressure on the molten lead in the pot; a further advancement of the cam lifts the plunger 90 to its normal position, if it has not already floated to the said position, this cam being so fashioned that the said pump plunger lever 95 is not actuated until the mouthpiece 87 of the pot is retired from the mold plate 91.

In this way the plunger 90, being relieved of the weight, and the pot retiring to its normal position, induces the plunger 90 to float up, the cam merely ensuring that the plunger 90 is retired above the holes 98 in the pump barrel 89 in readiness for each succeeding function.

Referring to Figure 14, the broken lines indicate the position of the pot when mouth piece is in contact with mold plate 91. The mouthpiece of the pot, which is preferably dovetailed to it, is provided with horizontal grooves 99 and 100, Fig. 3; there are a number of horizontal holes 101 perpendicular to these grooves suitably spaced along the mouthpiece interconnecting the two horizontal grooves 99 and 100 with the mold. There is communication between the holes 101 and the mold indicated at 94. The runner 93 is fashioned preferably in the manner indicated in Figure 3 and consists of a tapered frustoconical hole 87A extended laterally at 87B and 87C, and converging towards the mold; said tapered hole 87A is fitted with a tapered plug 87E having its inner end 87F of smaller diameter so that an annular space 87G surrounds it to form communication between the molten metal supply channel 92 and the runner 93. The said grooves being connected by vents 102 and 103, projecting inwardly in the pot; the vent 103, to discharge the surplus metal, the other, 102 being the air vent. By this method the circulation of metal in the mold is introduced which ensures the mold filling and the air to escape.

On the downward stroke of the plunger the process of expelling air from the mold and returning the surplus lead to the port is as follows The lead flows up through the channel 92 in the pot and is distributed through the two channels 87B and 87C, to the annular space 87G, from that annular space through the runner 93 into the mold 94 through the channel 93. It will be seen, any air in the mold is dispersed through the channel 101A into the vertical holes 101 up to the grooves 99 and into the conduit 102, when the mold is full surplus lead is projected through the chan- 'nel 101A, down the vertical holes 101 into groove 100 and along the vent 103 back to the pot.

Referring back to Figure 2, the plunger casing 73 consists of a series of Y pieces, one passage 73B of which takes the lower end of the tube 72, the other passage 73D forms a guide for the plungers 77. The nail holder 7 3A is split into two pieces, these being held in place by means of the gland 7 3E. A rubber washer 73F is inserted between the gland 73Ex and the flange 73G of the nail holder 73;

In action the nail falls down the passage 73D and is retained in the nail holder 73A until the downward motion of the plunger 77 forces the nail through the holder 73A which opens out under the influence of the plunger, receding to its normal position under the influen ce of the rubber washer 73F.

Referringto Figures 17 and 18, there is automatic trip mechanism, consisting of a double bell crank mounted on a vertical spindle 104, suitably attached to a horizontal bar 105; the said bell crank has two projecting members 106 and 107, the projection 106 is adapted to engage with a vertically operating cam 108 mounted on the same vertical spindle which transmits motion to the extracting grid 86, and a gate trimmer.

There is a member, 109, of the bell crank projecting therefrom to engage with one end of the connecting rod 110, while the other end of the said connecting rod is coupled to a pivotally mounted stop 111.

The member 107 of the bell crank is projected over the cylinder in such a manner that in the course of the revolution of the said cylinder a nail in the series of holes 74 in the cylinders 76 strikes the member 107 of the bell crank and turns it upon its spindle 104, to approximately the position indicated by broken lines in Figure 17, and through the medium of the connecting rod 110., the pivotally mounted stop 111 is turned upon its pivot approximately to the position indicated by dot and dash lines in Figure 17; in this way the said step is removed from direct alignment with a stud 112, which is secured to or cast integral with, the boss part 95A, and permits the spindle 97 to turn due to the influence of the weight 90C to perform pump ing operations.

In the event of the nailing mechanism not operating, and no nails entering the series of holes 74, the bell crank member is stationary and the stop lever 111 will remain in the position indicated in full linesin Figure 17, in alignment with the stud 112, and'pumpi'ng operations will stop, thus preventing molding what is known as dummy heads; that is merely casting heads with no nails attached thereto.

hat I claim as new and desire to secure 5 by Letters Patent is 1. Molding apparatus for molding machines, eon'iprising a pot for containing molten metal, a mold, means forming a conduit to deliver molten metal from said pot to said mold, a mouth-piece for said conduit having an opening registering with an opening in the mold, said mouth-piece being pro videdwith upper and lower substantially horizontal passages and with a substantially vertical passage connecting said upper and lower passages, the upper passage communicating with atmosphere and the lower passage with the pot, said mouthpiece being formed with vent hole communication with said mold and with said substantially vertical passage, serving as an outlet for air as well as overflow metal from said mold.

2. Molding apparatus tor molding machines, comprising a pot ior containing molten metal, a mold, means forming a conduit to deliver molten metal from said pot to said mold, a mouthpiece for said conduit having an opening registering with an opening in the mold, said mouthpiece being provided with upper and lower substantially horizontal passages and with a substantially vertical passage connecting said upper and lower passages, the upper passage communi- 3 eating with atmosphere and the lower passage with the pot, said mouthpiece being formed with a vent hole communicating with said mold and with said substantially vertical passage, serving as an outlet for air 4 as well as overflow metal from said mold, a pump in said pot including a plunger, a weighted lever for depressing said plunger, forcing the metal toward said mold, a second lever for raising said plunger independent of said weighted lever, means operative when the mouth-piece of said conduit is in communication with said mold for releasing said weighted lever, said lever being so correlated that the plunger lifting lever is depressed by the weighted lever, said weighted lever releas ing means being constructed to raise said weighted lever in advance of the lifting movement of said plunger, relieving the lat ter from the weight of said weighted lever and means for raising said plunger lifting lever after the separation of said mouth-piece from said mold.

3. Molding apparatus for molding machines, comprising a pot for containing molten metal, a mold, means forming a conduit to deliver molten metal from said pot to said mold, a mouth-piece for said conduit having an opening registering with an opening in the mold, said mouth-piece being provided with upper and lower substantially horizontal passages and with a substantially vertical passage connecting said upper and lower passages, the upper passage communicating with atmosphere and the lower passage with the act, said mouth-piece being formed with a vent hole communicating with said mold and with said substantially vertical passage, serving as an outlet for air as well as overflow metal from said mold, a pump in said pot including a plunger a rock shaft, a plunger lifting lever fixed to said rock shaft, means for raising said plunger lifting lever after the mouth-piece has separated from said mold, a weighted plunger depressing lever rotatably mounted on said rock shaft, operatively connected to said plunger for depressing the latter solely by gravity, said plunger operating levers having interengaging portions for causing the weighted lever to depress the plunger lifting lever, means for raising said weighted lever slightly in advance of the lifting movement ofsaid plunger lifting lever, and means releasing said weighted lever when said mouth-piece comes into contact with said mold.

Molding apparatus for molding macl llllOr; comprising a pot for containing molten metal, means forming a conduit to deliver molten metal from said pot to a mold, a rotat able drum having article holding portions arranged at intervals thereupon, the walls of said drum adjacent said article holding portions being adapted to be brought into operalive relation to said month-piece successively by rotation of said drum, and constituting a wall of the mold, and a face plate having a chamber bounded on the one handbythe said portion of said drum and on the other by said mouth-piece, constituting the body of the mold, means for imparting step by step rotation to said drum and means for advancing said mouth-piece and face plate into intimate contact with one another and with said drum when an article holding port-ion of the latter is in registry with said face plate.

5. Molding apparatus for molding machines claimed in claim 4t, the article holding portions of said drum each including a bushing fixed to said drum and having a bore for receiving the article, and a spring extending into the path of said article, to be displaced by said article thereby retaining the latter in position.

6. Molding apparatus for molding machines as claimed in claim 4:, the article holding portions of said drum each being constitn ted by a bushing secured to said drunrhavi ng bores therein for the reception of the arti ole, s} )rings arranged to be displaced by said article for retaining the latter in position, and means for ejecting the completed article when the drum has rotated to a position in which the article holding portion is no longer in mg istry with the body of the mold.

7. Molding apparatus for molding machines comprising a pot for containing metal, a mold, means forming a conduit to deliver molten metal from said pot to said mold, a mouth-piece for said conduit provided with upper and lower substantially horizontal passages, a recess in said mouth-piece, a plug detachably seating in said recess and having a passage comunicating with said conduit and adapted to communicate with said mold, said plug being formed with a vertical passage communicatingboth with said upper and lower horizontal passage and with a vent hole communicating with said mold and with said vertical passage serving as an outlet for air and overflow metal from said mold.

8. Molding apparatus formoldingmachines comprising a pot for containing molten metal, a conduit for delivering molten metal from said pot to said mold, a mouth-piece on said conduit constituting one Wall of said mold, a chambered face plate constituting the body of said mold and a rotatable drum forming magazine for holding articles on which portions are to be molded, said magazine constituting the opposite Wall of said mold, means for imparting step by step rotation to said drum to bring the articles to be molded into registry with the chamber of the face plate, means for advancing said mouth-piece and face plate into intimate contact with said drum, and withdrawing them from contact with said drum, said drum rotating means being constructed to move the finished article out of registry with said face plate when the molding operation has been completed, and means for ejecting the finished article.

In testimony whereof I affix my signature.

JOHN DENNISTON SMITH. 

